1. Field of the Invention
The present invention relates to a recording device, such as a facsimile machine utilizing electrophotography, and in particular to a mechanism for accurately positioning a transfer charger with respect to a photosensitive drum.
2. Prior Art
A conventional electrophotographic recording device is provided with a housing comprised of a lower cover and an upper cover pivotable with respect to the lower cover for opening and closing, a photosensitive drum mounted to the upper cover, and a transfer charger mounted to the lower cover. A pair of guide plates are provided to guide recording paper to the gap between the photosensitive drum and the transfer charger. The guide plates are mounted to the lower cover.
The gap between the cylindrical surface of the photosensitive drum and the transfer charger must be accurately adjusted in order to achieve a satisfactory transfer of the toner image and obtain a picture (printout) of good quality. For instance, the gap is about 1 to 2 mm and the permissible error is .+-.0.1 mm. But this is difficult because the upper cover and the lower cover to which the photosensitive drum and the transfer charger are respectively mounted are assembled such that they are movable for opening and closing. Moreover, the exit part of the guide plates must be aligned with the gap between the photosensitive drum and the transfer charger in order to avoid paper jamming. But this again requires delicate and time-consuming adjustment. Providing a mechanism for the accurate positioning of these components may unacceptably increase the cost of the recording device.